Try it

How this works

Basically all this does is use the Chrome Extension WebRequest API and Proxy API to intercept any requests to the top level domain .dat_site. When that TLD is requested, Chrome uses the Proxy API to redirect the request to the local Electron server at http://127.0.0.1:9989/ and from there the server loads the Dat (using sparse mode) and returns the page or file that was requested.

This'll require coming up with a way to simply parse Dat URLs in a regular web browser, as parse-dat-url doesn't work very well on the web (there's likely a fix that can be done with regular expressions but I suck at them so... yeah).

Provide the dat:// URL to the current site via the extension popup.

Have the extension automatically open the app in the background when a .dat_site is requested via the Native Messaging API.

Polyfill the Beaker Browser APIs (don't necessarily need all of them, just the ones to make sure the sites are viewable, e.g. Rotonde sites).

Use the omnibox API to let users just type the dat:// URL or the hash itself as a search to load the site.

Come up with a fallback for when the dat can't be found (Maybe a "Did you mean?" page or something).

Optional background functionality.

WebRTC support (for Chrome OS and providing a web proxy).

UDP support on Chrome OS.

Maybe support regular domain names the way Beaker Browser does, I don't know how this would be done via a browser extension but I feel like it might be possible (if well executed this could be useful for easing bandwidth/data use on certain sites).

Internet Explorer support? (I'm being ridiculous here, but again unsure if this is possible)

To-Do [Short term + more specific list]

Dat URL for current tab in the extension pop up.

Support for 404 pages by reading “fallback_page” in dat.json (updated this further to work the same way it does in Beaker Browser).

An button in the extension pop up to tell the app to download the entire Dat.

A button in the extension pop up to tell the app to delete the entire Dat.

A landing page for introducing users to the extension/app.

Display a badge for Dat sites.

The ability to submit dat links or hashes as searches in the extension (needs Dat parse for web). (Works via hacky method, needs lots of improving)

Fix how much the server app checks for the dat.json file (it seriously goes nuts, checks the network for dat.json again on every HTTP request).

Code something to let the extension know to hide the "Pin" or "Unpin" button (likely going to be more HTTP headers, for now).

Build a web page that displays a list of the Dats stored offline for clarity (this is the last thing I need before building a Mac OS X and Linux version).

A page for deleting dats and other information.

Get Travis CI working with this repo to auto-build Mac OS X and Linux versions.

Get AppVeyor working with this repo to auto-build Windows versions.

Provide an optional feature to convert dat:// URLs that aren't anchor links to anchor links (Useful for sites like Twitter).

Provide an option to have said links either stay in the dat:// URL format for Beaker Browser or other Dat apps, or to have them switch to the .dat_site domain name format for DatPart to open them (consider providing a context menu item for letting users on the fly decide what should be done).